The genus Clostridium is comprised of gram-positive, anaerobic, spore-forming bacilli. The natural habitat of these organisms is the environment and the intestinal tracts of humans and other animals. Indeed, clostridia are ubiquitous; they are commonly found in soil, dust, sewage, marine sediments, decaying vegetation, and mud. See e.g., P. H. A. Sneath et al., “Clostridium,” Bergey's Manual of Systematic Bacteriology, Vol. 2, pp. 1141-1200, Williams & Wilkins (1986). Despite the identification of approximately 100 species of Clostridium, only a small number have been recognized as etiologic agents of medical and veterinary importance. Nonetheless, these species are associated with very serious diseases, including botulism, tetanus, anaerobic cellulitis, gas gangrene, bacteremia, pseudomembranous colitis, and clostridial gastroenteritis.
Several strains of Clostridium botulinum produce toxins of significance to human and animal health. C. L. Hatheway, Clin. Microbiol. Rev. 3:66-98 (1990). The effects of these toxins range from diarrheal diseases that can cause destruction of the colon, to paralytic effects that can cause death. Particularly at risk for developing clostridial diseases are neonates and humans and animals in poor health (e.g., those suffering from diseases associated with old age or immunodeficiency diseases).
What is needed is an effective therapy against botulism that is free of dangerous side effects, is available in large supply at a reasonable price, and can be safely and gently delivered so that prophylactic application to infants is feasible. Safe and effective vaccine preparations for administration to those at risk of exposure to C. botulinum toxins are also needed.